Continuity mistake: When Alita is playing the street version of motor ball she knocks over Tanji. In the next shot Tanji is following her in the pack as she scores, then the shot switches back to him on the ground.
Continuity mistake: During the whole sequence when Alita wakes up in bed, in the closer shots the blanket directly by her pelvis is on top of the mattress, while in the shots from a wider angle part of the blanket dangles off the side. (00:04:00)
Revealing mistake: After breaking Zapan's nose, Alita jumps on the table of two guys and trash talks them into a fight; before they attack, the two bottles of beer on the table are different, one being the generic red and white Cerveza, the other with a peach colored label. When she kicks the CGI bottles, those are two identical Cerveza ones. (01:01:15)
Continuity mistake: During the sequence when Alita manages to get her revenge on Tanji, look when she is coming out of the curve with enough speed to be able to tackle him. In between shots the crowd behind the ramp has completely changed, with some bearded guy and a dude with a panama appearing out of nowhere, to mention just the most obvious. (00:19:40)
Continuity mistake: Alita just woke up at the beginning of the movie. When she sneaks downstairs checking out of the unfamiliar location, she suddenly has her hand on the railing between shots. (00:05:30)
Continuity mistake: As Alita punches Zapan and dispossesses him of his weapon, the large sword, in a rather unbelievable bit of CGI, flies off the side between two patrons at the table. Unless we assume a pinball-like bouncing trajectory, you can't explain how it ends up being back directly in front of Alita for her cool kick toss a moment after. (01:00:20)
Continuity mistake: In the unfortunate outcome of the encounter with Zapan in the alley, Tanji lies on the floor in two completely different ways. (01:27:20)
Continuity mistake: When Alita decks Tanji, he faceflops past a manhole. In the reaction shot that follows, Tanji is suddenly by the manhole, and the lighting of the scene is totally different from before. (00:19:45)
Continuity mistake: Grewishka makes his grand entrance inside the bar: as a poor schmuck asks "What's happened to him?", a guy in the background is sitting, but in the shot immediately after, he's standing and only after a moment he slowly sits down. (01:01:30)
Continuity mistake: Hugo is running away from Zapan; after the sequence of Alita's busted pipe we see him jump over a parapet onto a street underneath, rolling just past an incoming utility vehicle. In the overhead shot he lands right in front of a group of people including a rather conspicuous man with a pink shirt, but in the following shot almost everyone in the street is gone. (01:34:40)
Continuity mistake: Ido and his ex-wife are walking on a relatively narrow bridge with stalls on one side. When she says "clearly" to him admitting he did not destroy the body, a man with a backpack literally disappears between shots as he was walking past a woman in a white and blue shirt. (00:16:00)
Continuity mistake: In the battle with Grewishka and the other two murderous cyborgs, Ido loses his scythe that falls down with the sharp edge pointed towards his right. When Nyssiana disrobes, though, the scythe is turned the other way incorrectly, with the pointy end on the opposite side and the burner on the right. (00:28:15 - 00:29:00)
Continuity mistake: After Alita slides away from the Centurion, dog in hand, she freezes in the pose at the side of the road. To her left, witnessing the scene there's a woman wearing sandals and some rasta patterned pants. She is standing by the corner of the sidewalk, but when we see her after a brief reaction shot on Hugo, she is standing super close, literally in Alita's shadow (they both shifted away from the corner, technically). (00:11:15)